10. Spider-Man's Movie "Debut" - X-Men
On the X-Men: Special Edition DVD, there's a secret gag included where Storm (Halle Berry), Cyclops (James Marsden) and Jean Grey (Famke Janssen) are unexpectedly joined by a certain web-slinging superhero while running around the Statue Of Liberty.
During an outtake shot for the film's finale, stuntman Scott Leva is zipped into a Spider-Man suit and appears to "accidentally" stumble into the wrong movie, after which Cyclops quickly chases him off the set and everyone has a good laugh about it.
This is especially notable as the scene's release predates the first major live-action Spider-Man movie by over a year, technically giving fans their first semi-authorised look at Spidey in lifelike, big-budget action.
Curiously, Leva had also previously worn a Spidey suit to pose as a reference for the 1985 Spider-Man comic The Amazing Spider-Man #262. Neato.
How To Find It: This one's a piece of cake compared to some of the tricks on this list. From the DVD's main menu, simply select Special Features, then Theatrical Trailers, and after selecting Trailer A, press left to illuminate a flower. Finally, press enter.